Comparison of percutaneous vertebroplasty and conservative treatment for one level thoracolumbar osteoporotic compression fracture in a 3-year study

The efficacy of Mesh optimized versus standard percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures. Grid optimization (102 cases; 38 men, 64 women aged 67.3 ± 8.5) and traditional PVP groups (94 cases) were identified from 196 PVP patients treated from May 2016 to 2019. The optimal puncture site and angle forced bone cement into both groups before surgery. The main indexes were operation time, X-ray fluoroscopy times, bone cement injection volume, leakage, VAS, and injured vertebrae height. Preoperative general data were equivalent between groups (P > 0.05). All patients survived surgery without spinal cord injury, incision infection, pulmonary embolism, or death. The mesh optimization group had improved operation time (34.8 ± 6.5 min), fluoroscopy times (29.5 ± 5.5), bone cement injection volume (5.3 ± 2.1 ml), and bone cement permeability greater (3.9 percent; 4/98) than the standard PVP group (P < 0.05). Similarly, the grid optimization group had superior VAS scores (1.1 ± 0.6; 1.0 ± 0.3; and 0.9 ± 0.2) than the standard PVP group at 3 days, 3 months, and the last follow-up visit (P < 0.05). On day three after surgery, both had similar heights of injured vertebra's anterior and middle edges (P > 0.05). However, in the mesh optimization group, measurements improved to 1.8 ± 0.4 mm and (1.8 ± 0.3) mm by month three and to 1.7 ± 0.3 mm at last follow-up (P < 0.05). Mesh-optimized PVP with a mesh locator treats osteoporotic vertebral compression fractures more safely and effectively than regular PVP.

www.nature.com/scientificreports/body surface angle and body surface scale.Screening and treating patients at high risk of osteoporotic fracture are cost-effective, yet around two-thirds of annual OVCFs are misdiagnosed and untreated 2 .
Based on retrospective analysis of the data of 196 patients with lumbar OVCF treated by PVP in our hospital as well as the skin being visualized by preoperative CT data, we applied a grid locator to optimize key Hemipuncture points of PVP (skin puncture point, vertebral bony puncture point, target point of puncture needle in vertebral body) and puncture path to reduce the times of intraoperative "C" arm X-ray and find the best puncture site and angle, as well as avoiding nerve injury caused by poor puncture angle; The purpose of the comparison with traditional PVP surgery was that: (1) Discussion on the feasibility of optimizing the puncture point and puncture path of grid locator in PVP surgery before grid locator; (2) Conclusion on the advantages of using grid locator to optimize the path before operation; (3) Evaluate on the efficacy of PVP after using grid locator to optimize the path.

Inclusion and exclusion criteria
Inclusion criteria (1) Osteoporotic and a compression fracture in the single sequence of the lumbar spine, of which kyphosis Cobb angle < 40° without neurological symptoms; (2) The patients were treated with PVP of the optimized path of grid locator before operation; (3) The comparison with the patients who received the traditional PVP operation at the same term; (4) The main observation indexes include operation time, intraoperative fluoroscopy times, pain relief degree and bone cement leakage rate; (5) The case-control study.

General information
According to the above inclusion and exclusion criteria, 204 patients with lumbar osteoporotic compression fractures were treated with PVP from May 2016 to May 2019; a total of 196 patients were included in this study, which contains 64 males and 132 females; ages (68.3 ± 8.1 years old) with a range from 58 to 84 years old; course of diseases (2.1 ± 1.1 days) with a range from 0.5 to 5.4 days.
No Neurological symptoms occurred in the 196 patients, whose clinical symptoms were lower waist pain, tenderness, and percussion pain at the spinous process of the fracture site, Among whom 45 patients (23.0%) were unable to walk due to pain.
Wedge-shaped changes occurred in single lumbar vertebrae by X-ray and CT, as well as high signal changes by MRI T2WI.All patients had informed consent and signed the informed consent form.Moreover, all methods were carried out in accordance with relevant guidelines and regulations issued by the General Hospital of Northern Theater Command.All experimental protocols were approved by the General Hospital of Northern Theater Command approval committee.

The selection principle of the operation method
All 196 patients were in accordance with the preoperative application of the grid locator to optimize the key puncture point and puncture path of PVP, as well as the traditional PVP operation.The advantages and disadvantages of the two methods were explained to the patients and their families in detail before the operation, which was chosen by the patients or their families.

Case grouping
The total cases of the grid optimization group were 102, which included 38 males and 64 females, aged (67.3 ± 8.5 years old) with a range from 58 to 84 years old), the course of disease (2.3 ± 1.2 days) with the range from 0.8 to 5.4 days), among whom 73 cases had a definite history of trauma consisting of 38 cases of sprain, 33 cases of fall and 2 cases of traffic accident; the remaining 29 cases had no obvious history of trauma.Among them, 25 patients (24.5%) were unable to walk due to pain.The distribution of injured vertebrae: 59 cases of L1 vertebrae, 31 cases of L2 vertebrae, 8 cases of L3 vertebrae, 3 cases of L4 vertebrae, and 1 case of L5 vertebrae.
The traditional PVP group was in a total of 94 patients, including 26 males and 68 females, age (71.5 ± 5.6 years old) with the range from 62 to 82 years old), course of the disease (2.1 ± 1.1 days) with the range from 0.5 to 4.7 days, among whom 58 cases had a definite history of trauma, including 37 cases of sprain, 17 cases of fall, and 4 cases of traffic accident; the other 36 cases had no obvious history of trauma.Among them, 20 patients (21.3%) were unable to walk due to pain.The distribution of injured vertebrae: 52 cases of L1 vertebrae, 33 cases of L2 vertebrae, 7 cases of L3 vertebrae, 2 cases of L4 vertebrae.

Grid optimization group
The body surface grid locator was placed on the patient's damaged vertebrae before surgery (Fig. 1A).The fractured vertebrae and body surface location were reconstructed from a CT scan of the lumbar.In addition, we were required to import 3D reconstruction data by CT into Mimics 21.0 software (Materialise company, USA), applying a new mark to label the injured vertebrae and grid locator as well as fulfilling the reconstruction of vertebrae and grid locator (Fig. 1B,C).
Cylinders replaced puncture channels after repair.The cylinder's end was placed at point C, where the extension line of the contralateral pedicle's inner border meets the vertebral body's anterior edge.After that, we had to swing the other end, which was set at point B, the midway of the line between the vertebral body's upper and lower endplates and the tangent line of the pedicle's lateral edge, which horizontally transverses it.The penmarked skin piercing point is A (Fig. 1D).
The prone patient was given local anesthesia (lidocaine with a dose of 50-100 mg per patient), sterilized, and punctured at the preoperatively planned skin puncture spot (point A) (Fig. 2A).We found the spinal bone puncture point by "C" arm X-raying the "outside edge of the pedicle" and the transverse process's tangent line (point B, Fig. 2B).The core is removed, and the guidewire is implanted when the puncture needle tip reaches the inner pedicle.The guidewire tip touches the vertebral body's anterior edge and the contralateral pedicle's inner edge at the target site (point C, Fig. 2B).After checking the puncture path and crucial puncture spots, we inserted the working channel and applied bone cement.

Traditional PVP group
The body position and anesthesia mode were the same as those in the grid optimization group.Under the fluoroscopy of the "C" arm X-ray machine, "9 points" (left side) or "3 points" (right side) of pedicle projection of fractured vertebral body were selected as the entry point.Anteroposterior and lateral fluoroscopy showed that the puncture needle tip did not reach the spinal canal.Thus, we continued to pierce 0.5 cm and introduced a guide wire and working channel.The lateral X-ray fluoroscopy showed the guidewire tip in the anterior and center 1/3 of the vertebral body, whereas the anteroposterior showed it in the projection of the median spinous process.Traditional PVP-targeted intravertebral guidewire tip.

Evaluation index
Operation condition Operation time.To compare grid optimization group and traditional PVP group operation times, the time from disinfection of the operating area to bone cement setting was considered as min.
Intraoperative fluoroscopy times.The grid optimization group and typical PVP group were compared for intraoperative X-ray exposure on operators and patients by counting fluoroscopy times from the start of the procedure until puncture channel formation.
Amount injection of bone cement.The dose of bone cement delivered into the damaged vertebral body during surgery was measured by a scale accurate to 0.5 ml.
Bone cement leakage condition.Leakage has three types: type B: vertebral basilar vein to the posterior edge of the vertebral body and the anterior section of the dura mater; type S: vertebral segmental vein to the segmental vein; type C: vertebral cortical defect to any part around the vertebral body.

Visual analog scale (VAS)
The scale measured backache and lower limb discomfort severity.0 represents no discomfort, and 10 is the greatest.Patients choose one of 11 numbers to indicate their discomfort, and the standard scoring is 0-10.They were scored before the operation, 3 days after, 3 months after, and at the last follow-up.

Height of anterior and middle edge of the injured vertebra
The damaged vertebra's upper and lower endplates were the height of its anterior edge on the lumbar lateral X-ray.
After vertebral body compression fracture surgery, the injured vertebra's middle edge was the distance between the midpoints of the upper and lower endplates.

Statistical processing
SPSS 22.0 (IBM, USA) statistical software package was used for statistical analysis.The measurement data were analyzed by the Shapior-Wilk test to determine whether it was a normal distribution.Those which were in line with normal distribution and had the same variance were expressed as (x ± s).We adopted a t-test of two independent samples as well as a chi-square test to compare the measurement data in two groups.Moreover, the t-value and p-value, along with the α value of the test level, were obtained from 0.05 on both bilateral sides.

Intraoperative fluoroscopy times
The times of intraoperative fluoroscopy in the mesh optimization group was 29.5 ± 5.5, which was better than the traditional PVP group (38.0 ± 4.0) with statistical significance (t-value = 3.251, P-value = 0.025).The times www.nature.com/scientificreports/ of intraoperative fluoroscopy in the mesh optimization group were lower by 22.4% than in the traditional PVP group (Table 2).

Bone cement injection volume
In the mesh optimization group, the bone cement was fully diffused into the vertebral body (Fig. 3), of which the injection volume was (5.3 ± 2.1) ml; In the traditional PVP group, the bone cement was diffused into the puncture site, but the opposite side was not fully diffused (Fig. 3), of which the injection volume was (4.4 ± 1.5) ml.There was a significant difference in the amount of bone cement injected between the two groups (t = 1.738,P = 0.048).The amount of bone cement injected in the mesh optimization group was higher by 20.5% than in the traditional PVP group.

Bone cement leakage rate
There were 4 cases of bone cement penetration in the mesh optimization group (3.9%) and 20 cases in the traditional PVP group (21.9%).There was a significant difference in the incidence of bone cement penetration between the two groups (χ 2 = 12.701, P < 0.001).The penetration incidence of bone cement in the traditional PVP group was about 5.5 times higher than in the mesh optimization group.

VAS score of low back pain
The VAS score of the grid optimization group improved to (1.1 ± 0.6) points on the 3rd day after the operation, which was (0.9 ± 0.2) points at the last follow-up more than 1 year after the operation, while the VAS score of the traditional PVP group improved to (1.4 ± 0.6) points on the 3rd day after the operation, which was (1.1 ± 0.3) points at the last follow-up more than 1 year after operation (Table 3).There were statistically significant differences between the two groups at 3 days, 3 months, and the last follow-up (P < 0.05, Table 3).
The height of the anterior and middle edge of the injured vertebrae (cm) In the mesh optimization group, the height of the anterior edge of the injured vertebra recovered to (1.9 ± 0.3) cm on the 3rd day after the operation, which was maintained at (1.7 ± 0.3) cm at the last follow-up, more than 1 year after the operation; In the traditional PVP group, the height recovered to (1.8 ± 0.4) cm on the 3rd day after the operation, which maintained at (1.5 ± 0.4) cm at the last follow-up more than 1 year after the operation.In addition to the third day after the operation, the height of the anterior edge of the injured vertebra in the mesh optimization group was superior to the traditional group at 3 months after the operation, and the last follow-up with statistically significant.(P < 0.05, Table 3).
In the mesh optimization group, the height of the middle edge of the injured vertebra recovered to (1.9 ± 0.6) cm on the third day after the operation, which remained at (1.7 ± 0.3) cm at the last follow-up more than one year after the operation; while the traditional PVP group recovered to (1.8 ± 0.2) cm on the 3rd day after the operation, which maintained at (1.5 ± 0.3) cm at the last follow-up more than 1 year after the operation.In addition to the third day after the operation, the height of the middle edge of the injured vertebrae in the mesh optimization group was higher than the traditional PVP group 3 months after the operation and the last follow-up with statistically significant (P < 0.05, Table 3).

Discussion
Fluoroscopy is not required for skin entry point selection.The grid recognizes your point on the skin surface as the intersection of horizontal and vertical lines.After choosing point A, experienced doctors can puncture fast.Mesh optimization had a considerably lower fluoroscopy frequency than a puncture.
PVP was used to treat 196 OVCF patients, and mesh optimization reduced fluoroscopy and operation time.The frequency and time of single puncture fluoroscopy in vertebroplasty are mainly used to select the skin entry point (point A) and bone entry point (point B).The traditional single puncture approach involves an expert operator selecting the skin entrance point under fluoroscopy and the bone entry point by altering the needle angle.However, if the puncture needle angle is not correct to enter the vertebral body through the pedicle, we must reselect the skin entry site and vertebral bone entry point, increasing fluoroscopy frequency and worsening soft tissue and joint capsule injury.According to the rebuilt preoperative CT data of the fractured vertebral body, we designed the puncture needle target point (point C) and bone entrance point (point B) to limit unilateral puncture fluoroscopy and save operation time 9 .We also created a reverse extension line to the skin surface through the connection between points C and B to find the skin entry location (point A), which a preoperative body surface locator may validate without fluoroscopy.In the selection of vertebral bony puncture point (point B), Yan et al. 10 proposed that In unilateral puncture, the puncture point should be 5 mm outside the pedicle and the transverse process midpoint, while Li Yuwei et al. 11 proposed that Puncture the transverse process tip about 10 mm outside the pedicle.This study concludes that 5 mm or 10 mm on the outer edge of the pedicle could not be determined by intraoperative fluoroscopy.According to the previous study 12 , the width of the base of the segmental pedicle and vertebral body in thoracic 4-lumbar 5 gradually increased.In this investigation, we picked the middle tangent of the transverse process and the "outside edge of the pedicle" after moving one

Figure 1 .
Figure 1.(A) Key puncture points of preoperative mesh optimization.(B) X-ray fluoroscopy showing the intersection of the midpoint of the line between the upper and lower endplates of the vertebral body and the tangent of the lateral edge of the pedicle of the vertebral body.(C) X-ray fluoroscopy to determine the target point in the vertebral body, where the tip of the guidewire reached the inner edge of the contralateral pedicle.(D) X-ray fluoroscopy showing the tip of the guidewire reaching the anterior edge of the vertebral body.

Figure 2 .
Figure 2. (A) X-ray showing that the bone cement was fully diffused into the vertebral body in the mesh optimization group, (B) X-ray showing the healing of injured vertebral body. https://doi.org/10.1038/s41598-023-36905-8

Figure 3 .
Figure 3. (A) X-ray showing that the bone cement was diffused into the puncture site in the traditional PVP group, (B) X-ray showing the contralateral side was not fully diffused.

Table 1 .
Comparison of preoperative baseline data of osteoporotic vertebral compression fractures between the grid optimization group and traditional PVP group.

Table 2 .
Comparison of the operation time, fluoroscopy times, bone cement injection volume and bone cement permeability in patients with osteoporotic vertebral compression fractures between the mesh optimization group and traditional PVP group.Number of cases Operation time (min) Perspective time (min) Bone cement injected volume (ml)

Table 3 .
Comparison of postoperative VAS score, the height of the anterior and middle edge of injured vertebra in patients with osteoporotic vertebral compression fractures between mesh optimization group and traditional PVP group.PO Post Operative.